Peru’s officials have a serious situation on their hands and only careful, broad and independent testing can really answer what has been really happening offshore. The information is still scarce, numbers do not match and reports vary in regard to what animals have been involved in this unprecedented die off of marine life. This die off is very complicated and nobody should be off the hook until it is all investigated in and out (preferably by independent team, that does not include US NOAA).
Here is why it is very complicated:
1. Species involved. It is complicated because of species that have been dying off and species that HAVE NOT been dying off. So far in regard to mortalities we have:
- anchovies (supposedly found at sea by the Peruvian Sea Institute and taken for testing, based on the Guardian report from February 10, 2012. Nobody talked about it ever since)
- other fish of various species (Pery 21 reported on April 11, that fishermen in San Jose Mórrope reported dead fish of various species, not specified how many though)
- sea lions(the first report of dozen sea lions came on April 11, reported by Peru 21 where a dozen of dead sea lions were found along with dolphins and fish in San Jose Mórrope. Recent report also indicates 5 more dead sea lions in Lambayeque as of April 28-30 )
- birds (this is a new development and includes 2 species: pelicans and boobies found dead in various decomposition states in Lambayeque. Numbers vary again, IMARPE reports 538 dead pelicans and 54 dead boobies, other reports are as high as 1200 dead birds)
- one dead sea turtle (another recent report, the turtle was found along with 5 dead sea lions and dead birds)
- dolphins (the reports are conflicting about everything in regard to dolphins, it seems that at least 3 species are involved: bottlenose, common and Burmeister’s porpoises. Numbers vary too, IMARPE insists on 877 others say as many as 3000)
Species that ARE NOT a part of this die off: whales (except for a beaked whale stranded in Paracas on February 6, 2012), sharks, rays, crabs.
Why Morbillivirus Suggestion Does Not Explain This Die Off
Peruvian authorities have been talking a lot about morbillivirus as a possible cause. Read our previous blog post why we think it is not the case. Additionally, Morbillivirus is species specific and pinnipeds have their own strain, not like cetaceans. More importantly birds are not infected by morbillivirus. So to think that dolphins, porpoises and seal lions got different strains of morbillivirus at the same time is extremely bizarre, and the birds do not fit at all in this explanation. In fact researchers separate marine morbilliviruses into 3 groups: Phocine distemper virus, Dolphin distemper virus and Porpoise distemper virus, and they are species specific (Fenner’s Veterinary Virology, 2011)
Why Biotoxins Such As Algae Bloom, Red Tide, Domoic Acid, Brevetoxins Do Not Explain This Die Off Either
BPZ oil company is probably very happy that dead pelicans were found. They think they can breathe easily now, but not so fast and here is why. If pelicans, bobbies, sea lions, dolphins and porpoises ingested contaminated fish where is this dead fish? Apart from two reports (anchovies at sea on February 10 and some reports of dead fish on April 11) we have not seen any significant fish die off. For example a well documented and established marine life die off in Arabian gulf region was indeed due to red tide outbreak and “Regional news agencies reported that thousands of tons of fish and marine mammals were killed; in Dibba Al-Hassan, over 650 tons of dead fish washed ashore and in Khor Fakkan more that 700 tons were reported” (Richlen et al., 2010, p. 166). Nothing like this have been seen in Peru. We also do not see other species that has been seen to die off as a result of the toxins, such as crabs, sharks, rays, whales, etc. See the graphic below of how brevetoxins work their way up the chain.
Another thing that complicates the case is that toxins just like morbillivirus can be found in wild populations without causing any die offs. THIS IS VERY IMPORTANT. So if the Peruvian authorities would say that they found presence of morbillivirus or toxins such as brevetoxins, etc. it DOES NOT MEAN that these factors caused the die off. Here is the paragraph from the study that found brevetoxins in water and in dolphins in Florida:
“The high abundance of K. brevis in water samples collected concurrently with detectable brevetoxins (parent toxins and metabolites) in dolphin urine and feces indicates recent exposure to, and excretion of brevetoxins. However, this exposure was not associated with a spike in dolphin mortalities similar to those seen in large dolphin die-offs such as that occurring in St. Joseph Bay, Florida, in 2004 (Flewelling et al. 2005), and all brevetoxin-positive dolphins in this study were still alive at the conclusion of this study. In fact, the question has been raised as to whether dolphin populations not commonly exposed to red tide (i.e., St. Joseph Bay) are more susceptible to high mortality than populations that frequently experience them (i.e., Sarasota Bay) (Van Dolah 2005)” (Fire et al., 2008, p. 841)
So when the Peruvian authorities finally issue their report look for CONCENTRATION and not just presence of toxins, because the presence of toxins or morbillivirus alone should not be considered the reason for the die off.
Strange and Unexplained Observations
This die off is strange in regard to several things:
1. Timing. Dolphins started washing ashore in February, maybe earlier. At first they were not very decomposed. As time progressed more decomposed carcasses started to show up, BUT also freshly dead ones. The sea lions and birds were found much later, but why exactly? If it was the fish they all ate, should they have been washing ashore roughly at the same time?
2. Live stranded dolphins. Due to the fact that the area is remote, it is entirely possible that many stranded alive and died afterwards. In fact there was at least one report about live stranded dolphin and other reports also stated that at least some dolphins might stranded alive.
3. Where is the dead fish if it was the reason for die off?
4. How could different strains of morbillivirus affect dolphins, sea lions and porpoises at the same time? Why the birds are dead too as they do not get this type of virus?
Some Things To Consider
Interestingly, some mysterious die offs have been happening before and many remain unsolved even today. For example the case of Mediterranian monk seals in 1997 where 100 dead seals washed ashore (Hall & Harwood, 2008). Another case was reported in Texas in 1992 where nearly 220 dead dolphins have been washing ashore. The cause was never established, but the runoff from pesticides have been discussed as one possible cause (Hall & Harwood, 2008). Finally, another report about die off in Mexico in 1995 blames an unknown toxic substance as a cause: “Based on data presented here, we believe that the most plausible cause forthe die-offs in the Upper Gulf of California is the discharge of an unknown toxic substance in the water. The only two obvious common factors amongthe species killed are that all breathe air and that most or all feed on smallfish (e.g., sardines). The only other marine mammal species sighted in the areaat the time of the die-offs were blue whales (at least 18 individuals) and graywhales (three individuals), but none of these were killed. Blue whales feed onplankton and gray whales on amphipods from the ocean floor. Whether thetoxic substance was acquired from the prey or from the water is unknown.We suggest that the marine mammals and birds died because a toxic substance was discharged in or near areas where their prey concentrate” (p. 633)”
The suggestions that morbillivirus or biotoxins are responsible have to be taken carefully because wild dolphins have been shown to have both in their system and not die. The cause for Peru’s marine life die off could include several factors. The presence of live stranded beaked whale and some live stranded dolphins along with acoustic trauma reports means that the oil company is not off the hook yet. The presence of dead birds makes a hole in morbillivirus hypothesis. The absence of significant numbers of dead fish as well as other species (whales, sharks, crabs) makes a hole in biotoxins hypothesis. The ongoing nature of this die off is strange, and it has to be noted that the oil company is still doing its survey that will end in May. The proximity of the survey area to the die off area is very suspicious to say the least. Seismic surveys could have also affected prey movements, abundance, etc. The bottom line is: read very carefully what the officials will be saying in regard to causes, as this die off is both unprecedented and complicated.
UPDATE 05/01/2012: Peruvian authorities came up with more exotic hypothesis about what happened. The latest is that pelicans died of starvation. And the fact that this happens together with dolphins’ massive die off, dead sea lions, etc in the same area and at the same time does not seem to matter.
Bricelj et al., (2012), Trophic transfer of brevetoxins to the benthic macrofaunal community during a bloom of the harmful dinoflagellate Karenia brevis in Sarasota Bay, Florida, Harmful Algae, 16, 27-34.
Fenner’s Veterinary Virology, (2011). Paramyxoviridae, Veterinary Virology.
Fire et al., (2008), Florida red tide and brevetoxins: Association and exposure in live resident bottlenose dolphins (Tursiops truncatus) in the eastern Gulf of Mexico, U.S.A., Marine Mammal Science, 24(4), 831-844.
Hall & Harwood, (2008), Mass Mortality, In Perrin et al., Encyclopedia of Marine Mammals, 2nd. edition, New York: Academic Press.
Richlen et al., (2010), The catastrophic 2008–2009 red tide in the Arabian gulf region, with observations on the identification and phylogeny of the fish-killing dinoflagellate Cochlodinium polykrikoides, Harmful Algae, 9, 163-172.